/*
** $Id: lvm.c,v 2.63.1.4 2009/07/01 21:10:33 roberto Exp $
** Lua virtual machine
** See Copyright Notice in lua.h
*/


#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#define lvm_c
#define LUA_CORE

#include "lua.h"

#include "ldebug.h"
#include "ldo.h"
#include "lfunc.h"
#include "lgc.h"
#include "lobject.h"
#include "lopcodes.h"
#include "lstate.h"
#include "lstring.h"
#include "ltable.h"
#include "ltm.h"
#include "lvm.h"
#include "lrotable.h"


/* limit for table tag-method chains (to avoid loops) */
#define MAXTAGLOOP  100

#if defined LUA_NUMBER_INTEGRAL
LUA_NUMBER luai_ipow(LUA_NUMBER a, LUA_NUMBER b)
{
    if (b < 0)
        return 0;
    else if (b == 0)
        return 1;
    else
    {
        LUA_NUMBER c = 1;
        for (;;)
        {
            if (b & 1)
                c *= a;
            b = b >> 1;
            if (b == 0)
                return c;
            a *= a;
        }
    }
}
#endif

const TValue *luaV_tonumber(const TValue *obj, TValue *n)
{
    lua_Number num;
    if (ttisnumber(obj)) return obj;
    if (ttisstring(obj) && luaO_str2d(svalue(obj), &num))
    {
        setnvalue(n, num);
        return n;
    }
    else
        return NULL;
}


int luaV_tostring(lua_State *L, StkId obj)
{
    if (!ttisnumber(obj))
        return 0;
    else
    {
        char s[LUAI_MAXNUMBER2STR];
        ptrdiff_t objr = savestack(L, obj);
        lua_Number n = nvalue(obj);
        lua_number2str(s, n);
        setsvalue2s(L, restorestack(L, objr), luaS_new(L, s));
        return 1;
    }
}


static void traceexec(lua_State *L, const Instruction *pc)
{
    lu_byte mask = L->hookmask;
    const Instruction *oldpc = L->savedpc;
    L->savedpc = pc;
    if ((mask & LUA_MASKCOUNT) && L->hookcount == 0)
    {
        resethookcount(L);
        luaD_callhook(L, LUA_HOOKCOUNT, -1);
    }
    if (mask & LUA_MASKLINE)
    {
        Proto *p = ci_func(L->ci)->l.p;
        int npc = pcRel(pc, p);
        int newline = getline(p, npc);
        /* call linehook when enter a new function, when jump back (loop),
           or when enter a new line */
        if (npc == 0 || pc <= oldpc || newline != getline(p, pcRel(oldpc, p)))
            luaD_callhook(L, LUA_HOOKLINE, newline);
    }
}


static void callTMres(lua_State *L, StkId res, const TValue *f,
                      const TValue *p1, const TValue *p2)
{
    ptrdiff_t result = savestack(L, res);
    setobj2s(L, L->top, f);  /* push function */
    setobj2s(L, L->top + 1, p1); /* 1st argument */
    setobj2s(L, L->top + 2, p2); /* 2nd argument */
    luaD_checkstack(L, 3);
    L->top += 3;
    luaD_call(L, L->top - 3, 1);
    res = restorestack(L, result);
    L->top--;
    setobjs2s(L, res, L->top);
}



static void callTM(lua_State *L, const TValue *f, const TValue *p1,
                   const TValue *p2, const TValue *p3)
{
    setobj2s(L, L->top, f);  /* push function */
    setobj2s(L, L->top + 1, p1); /* 1st argument */
    setobj2s(L, L->top + 2, p2); /* 2nd argument */
    setobj2s(L, L->top + 3, p3); /* 3th argument */
    luaD_checkstack(L, 4);
    L->top += 4;
    luaD_call(L, L->top - 4, 0);
}


void luaV_gettable(lua_State *L, const TValue *t, TValue *key, StkId val)
{
    int loop;
    TValue temp;
    for (loop = 0; loop < MAXTAGLOOP; loop++)
    {
        const TValue *tm;
        if (ttistable(t) || ttisrotable(t))    /* `t' is a table? */
        {
            void *h = ttistable(t) ? hvalue(t) : rvalue(t);
            const TValue *res = ttistable(t) ? luaH_get((Table *)h, key) : luaH_get_ro(h, key); /* do a primitive get */
            if (!ttisnil(res) ||  /* result is no nil? */
                    (tm = fasttm(L, ttistable(t) ? ((Table *)h)->metatable : (Table *)luaR_getmeta(h), TM_INDEX)) == NULL) /* or no TM? */
            {
                setobj2s(L, val, res);
                return;
            }
            /* else will try the tag method */
        }
        else if (ttisnil(tm = luaT_gettmbyobj(L, t, TM_INDEX)))
            luaG_typeerror(L, t, "index");
        if (ttisfunction(tm) || ttislightfunction(tm))
        {
            callTMres(L, val, tm, t, key);
            return;
        }
        /* else repeat with `tm' */
        setobj(L, &temp, tm);  /* avoid pointing inside table (may rehash) */
        t = &temp;
    }
    luaG_runerror(L, "loop in gettable");
}


void luaV_settable(lua_State *L, const TValue *t, TValue *key, StkId val)
{
    int loop;
    TValue temp;
    setnilvalue(L->top);
    L->top++;
    fixedstack(L);
    for (loop = 0; loop < MAXTAGLOOP; loop++)
    {
        const TValue *tm;
        if (ttistable(t) || ttisrotable(t))    /* `t' is a table? */
        {
            void *h = ttistable(t) ? hvalue(t) : rvalue(t);
            TValue *oldval = ttistable(t) ? luaH_set(L, (Table *)h, key) : NULL; /* do a primitive set */
            if ((oldval && !ttisnil(oldval)) ||  /* result is no nil? */
                    (tm = fasttm(L, ttistable(t) ? ((Table *)h)->metatable : (Table *)luaR_getmeta(h), TM_NEWINDEX)) == NULL) /* or no TM? */
            {
                if (oldval)
                {
                    L->top--;
                    unfixedstack(L);
                    setobj2t(L, oldval, val);
                    ((Table *)h)->flags = 0;
                    luaC_barriert(L, (Table *)h, val);
                }
                return;
            }
            /* else will try the tag method */
        }
        else if (ttisnil(tm = luaT_gettmbyobj(L, t, TM_NEWINDEX)))
            luaG_typeerror(L, t, "index");
        if (ttisfunction(tm) || ttislightfunction(tm))
        {
            L->top--;
            unfixedstack(L);
            callTM(L, tm, t, key, val);
            return;
        }
        /* else repeat with `tm' */
        setobj(L, &temp, tm);  /* avoid pointing inside table (may rehash) */
        t = &temp;
        setobj2s(L, L->top - 1, t); /* need to protect value from EGC. */
    }
    luaG_runerror(L, "loop in settable");
}


static int call_binTM(lua_State *L, const TValue *p1, const TValue *p2,
                      StkId res, TMS event)
{
    const TValue *tm = luaT_gettmbyobj(L, p1, event);  /* try first operand */
    if (ttisnil(tm))
        tm = luaT_gettmbyobj(L, p2, event);  /* try second operand */
    if (ttisnil(tm)) return 0;
    callTMres(L, res, tm, p1, p2);
    return 1;
}


static const TValue *get_compTM(lua_State *L, Table *mt1, Table *mt2,
                                TMS event)
{
    const TValue *tm1 = fasttm(L, mt1, event);
    const TValue *tm2;
    if (tm1 == NULL) return NULL;  /* no metamethod */
    if (mt1 == mt2) return tm1;  /* same metatables => same metamethods */
    tm2 = fasttm(L, mt2, event);
    if (tm2 == NULL) return NULL;  /* no metamethod */
    if (luaO_rawequalObj(tm1, tm2))  /* same metamethods? */
        return tm1;
    return NULL;
}


static int call_orderTM(lua_State *L, const TValue *p1, const TValue *p2,
                        TMS event)
{
    const TValue *tm1 = luaT_gettmbyobj(L, p1, event);
    const TValue *tm2;
    if (ttisnil(tm1)) return -1;  /* no metamethod? */
    tm2 = luaT_gettmbyobj(L, p2, event);
    if (!luaO_rawequalObj(tm1, tm2))  /* different metamethods? */
        return -1;
    callTMres(L, L->top, tm1, p1, p2);
    return !l_isfalse(L->top);
}


static int l_strcmp(const TString *ls, const TString *rs)
{
    const char *l = getstr(ls);
    size_t ll = ls->tsv.len;
    const char *r = getstr(rs);
    size_t lr = rs->tsv.len;
    for (;;)
    {
        int temp = strcoll(l, r);
        if (temp != 0) return temp;
        else    /* strings are equal up to a `\0' */
        {
            size_t len = strlen(l);  /* index of first `\0' in both strings */
            if (len == lr)  /* r is finished? */
                return (len == ll) ? 0 : 1;
            else if (len == ll)  /* l is finished? */
                return -1;  /* l is smaller than r (because r is not finished) */
            /* both strings longer than `len'; go on comparing (after the `\0') */
            len++;
            l += len;
            ll -= len;
            r += len;
            lr -= len;
        }
    }
}


int luaV_lessthan(lua_State *L, const TValue *l, const TValue *r)
{
    int res;
    if (ttype(l) != ttype(r))
        return luaG_ordererror(L, l, r);
    else if (ttisnumber(l))
        return luai_numlt(nvalue(l), nvalue(r));
    else if (ttisstring(l))
        return l_strcmp(rawtsvalue(l), rawtsvalue(r)) < 0;
    else if ((res = call_orderTM(L, l, r, TM_LT)) != -1)
        return res;
    return luaG_ordererror(L, l, r);
}


static int lessequal(lua_State *L, const TValue *l, const TValue *r)
{
    int res;
    if (ttype(l) != ttype(r))
        return luaG_ordererror(L, l, r);
    else if (ttisnumber(l))
        return luai_numle(nvalue(l), nvalue(r));
    else if (ttisstring(l))
        return l_strcmp(rawtsvalue(l), rawtsvalue(r)) <= 0;
    else if ((res = call_orderTM(L, l, r, TM_LE)) != -1)  /* first try `le' */
        return res;
    else if ((res = call_orderTM(L, r, l, TM_LT)) != -1)  /* else try `lt' */
        return !res;
    return luaG_ordererror(L, l, r);
}


int luaV_equalval(lua_State *L, const TValue *t1, const TValue *t2)
{
    const TValue *tm;
    lua_assert(ttype(t1) == ttype(t2));
    switch (ttype(t1))
    {
    case LUA_TNIL:
        return 1;
    case LUA_TNUMBER:
        return luai_numeq(nvalue(t1), nvalue(t2));
    case LUA_TBOOLEAN:
        return bvalue(t1) == bvalue(t2);  /* true must be 1 !! */
    case LUA_TLIGHTUSERDATA:
    case LUA_TROTABLE:
    case LUA_TLIGHTFUNCTION:
        return pvalue(t1) == pvalue(t2);
    case LUA_TUSERDATA:
    {
        if (uvalue(t1) == uvalue(t2)) return 1;
        tm = get_compTM(L, uvalue(t1)->metatable, uvalue(t2)->metatable,
                        TM_EQ);
        break;  /* will try TM */
    }
    case LUA_TTABLE:
    {
        if (hvalue(t1) == hvalue(t2)) return 1;
        tm = get_compTM(L, hvalue(t1)->metatable, hvalue(t2)->metatable, TM_EQ);
        break;  /* will try TM */
    }
    default:
        return gcvalue(t1) == gcvalue(t2);
    }
    if (tm == NULL) return 0;  /* no TM? */
    callTMres(L, L->top, tm, t1, t2);  /* call TM */
    return !l_isfalse(L->top);
}


void luaV_concat(lua_State *L, int total, int last)
{
    lu_mem max_sizet = MAX_SIZET;
    if (G(L)->memlimit < max_sizet) max_sizet = G(L)->memlimit;
    do
    {
        StkId top = L->base + last + 1;
        int n = 2;  /* number of elements handled in this pass (at least 2) */
        if (!(ttisstring(top - 2) || ttisnumber(top - 2)) || !tostring(L, top - 1))
        {
            if (!call_binTM(L, top - 2, top - 1, top - 2, TM_CONCAT))
            {
                /* restore 'top' pointer, since stack might have been reallocted */
                top = L->base + last + 1;
                luaG_concaterror(L, top - 2, top - 1);
            }
        }
        else if (tsvalue(top - 1)->len == 0)  /* second op is empty? */
            (void)tostring(L, top - 2);  /* result is first op (as string) */
        else
        {
            /* at least two string values; get as many as possible */
            size_t tl = tsvalue(top - 1)->len;
            char *buffer;
            int i;
            fixedstack(L);
            /* collect total length */
            for (n = 1; n < total && tostring(L, top - n - 1); n++)
            {
                size_t l = tsvalue(top - n - 1)->len;
                if (l >= max_sizet - tl) luaG_runerror(L, "string length overflow");
                tl += l;
            }
            G(L)->buff.n = tl;
            buffer = luaZ_openspace(L, &G(L)->buff, tl);
            tl = 0;
            for (i = n; i > 0; i--) /* concat all strings */
            {
                size_t l = tsvalue(top - i)->len;
                memcpy(buffer + tl, svalue(top - i), l);
                tl += l;
            }
            setsvalue2s(L, top - n, luaS_newlstr(L, buffer, tl));
            luaZ_resetbuffer(&G(L)->buff);
            unfixedstack(L);
        }
        total -= n - 1; /* got `n' strings to create 1 new */
        last -= n - 1;
    }
    while (total > 1);    /* repeat until only 1 result left */
}


static void Arith(lua_State *L, StkId ra, const TValue *rb,
                  const TValue *rc, TMS op)
{
    TValue tempb, tempc;
    const TValue *b, *c;
    if ((b = luaV_tonumber(rb, &tempb)) != NULL &&
            (c = luaV_tonumber(rc, &tempc)) != NULL)
    {
        lua_Number nb = nvalue(b), nc = nvalue(c);
        switch (op)
        {
        case TM_ADD:
            setnvalue(ra, luai_numadd(nb, nc));
            break;
        case TM_SUB:
            setnvalue(ra, luai_numsub(nb, nc));
            break;
        case TM_MUL:
            setnvalue(ra, luai_nummul(nb, nc));
            break;
        case TM_DIV:
            setnvalue(ra, luai_lnumdiv(nb, nc));
            break;
        case TM_MOD:
            setnvalue(ra, luai_lnummod(nb, nc));
            break;
        case TM_POW:
            setnvalue(ra, luai_numpow(nb, nc));
            break;
        case TM_UNM:
            setnvalue(ra, luai_numunm(nb));
            break;
        default:
            lua_assert(0);
            break;
        }
    }
    else
    {
        ptrdiff_t br = savestack(L, rb);
        ptrdiff_t cr = savestack(L, rc);
        if (!call_binTM(L, rb, rc, ra, op))
        {
            luaG_aritherror(L, restorestack(L, br), restorestack(L, cr));
        }
    }
}



/*
** some macros for common tasks in `luaV_execute'
*/

#define runtime_check(L, c) { if (!(c)) break; }

#define RA(i)   (base+GETARG_A(i))
/* to be used after possible stack reallocation */
#define RB(i)   check_exp(getBMode(GET_OPCODE(i)) == OpArgR, base+GETARG_B(i))
#define RC(i)   check_exp(getCMode(GET_OPCODE(i)) == OpArgR, base+GETARG_C(i))
#define RKB(i)  check_exp(getBMode(GET_OPCODE(i)) == OpArgK, \
    ISK(GETARG_B(i)) ? k+INDEXK(GETARG_B(i)) : base+GETARG_B(i))
#define RKC(i)  check_exp(getCMode(GET_OPCODE(i)) == OpArgK, \
    ISK(GETARG_C(i)) ? k+INDEXK(GETARG_C(i)) : base+GETARG_C(i))
#define KBx(i)  check_exp(getBMode(GET_OPCODE(i)) == OpArgK, k+GETARG_Bx(i))


#define dojump(L,pc,i)  {(pc) += (i); luai_threadyield(L);}


#define Protect(x)  { L->savedpc = pc; {x;}; base = L->base; }


#define arith_op(op,tm) { \
        TValue *rb = RKB(i); \
        TValue *rc = RKC(i); \
        if (ttisnumber(rb) && ttisnumber(rc)) { \
          lua_Number nb = nvalue(rb), nc = nvalue(rc); \
          setnvalue(ra, op(nb, nc)); \
        } \
        else \
          Protect(Arith(L, ra, rb, rc, tm)); \
      }



void luaV_execute(lua_State *L, int nexeccalls)
{
    LClosure *cl;
    StkId base;
    TValue *k;
    const Instruction *pc;
reentry:  /* entry point */
    lua_assert(isLua(L->ci));
    pc = L->savedpc;
    cl = &clvalue(L->ci->func)->l;
    base = L->base;
    k = cl->p->k;
    /* main loop of interpreter */
    for (;;)
    {
        const Instruction i = *pc++;
        StkId ra;
        if ((L->hookmask & (LUA_MASKLINE | LUA_MASKCOUNT)) &&
                (--L->hookcount == 0 || L->hookmask & LUA_MASKLINE))
        {
            traceexec(L, pc);
            if (L->status == LUA_YIELD)    /* did hook yield? */
            {
                L->savedpc = pc - 1;
                return;
            }
            base = L->base;
        }
        /* warning!! several calls may realloc the stack and invalidate `ra' */
        ra = RA(i);
        lua_assert(base == L->base && L->base == L->ci->base);
        lua_assert(base <= L->top && L->top <= L->stack + L->stacksize);
        lua_assert(L->top == L->ci->top || luaG_checkopenop(i));
        switch (GET_OPCODE(i))
        {
        case OP_MOVE:
        {
            setobjs2s(L, ra, RB(i));
            continue;
        }
        case OP_LOADK:
        {
            setobj2s(L, ra, KBx(i));
            continue;
        }
        case OP_LOADBOOL:
        {
            setbvalue(ra, GETARG_B(i));
            if (GETARG_C(i)) pc++;  /* skip next instruction (if C) */
            continue;
        }
        case OP_LOADNIL:
        {
            TValue *rb = RB(i);
            do
            {
                setnilvalue(rb--);
            }
            while (rb >= ra);
            continue;
        }
        case OP_GETUPVAL:
        {
            int b = GETARG_B(i);
            setobj2s(L, ra, cl->upvals[b]->v);
            continue;
        }
        case OP_GETGLOBAL:
        {
            TValue g;
            TValue *rb = KBx(i);
            sethvalue(L, &g, cl->env);
            lua_assert(ttisstring(rb));
            Protect(luaV_gettable(L, &g, rb, ra));
            continue;
        }
        case OP_GETTABLE:
        {
            Protect(luaV_gettable(L, RB(i), RKC(i), ra));
            continue;
        }
        case OP_SETGLOBAL:
        {
            TValue g;
            sethvalue(L, &g, cl->env);
            lua_assert(ttisstring(KBx(i)));
            Protect(luaV_settable(L, &g, KBx(i), ra));
            continue;
        }
        case OP_SETUPVAL:
        {
            UpVal *uv = cl->upvals[GETARG_B(i)];
            setobj(L, uv->v, ra);
            luaC_barrier(L, uv, ra);
            continue;
        }
        case OP_SETTABLE:
        {
            Protect(luaV_settable(L, ra, RKB(i), RKC(i)));
            continue;
        }
        case OP_NEWTABLE:
        {
            int b = GETARG_B(i);
            int c = GETARG_C(i);
            Table *h;
            Protect(h = luaH_new(L, luaO_fb2int(b), luaO_fb2int(c)));
            sethvalue(L, RA(i), h);
            Protect(luaC_checkGC(L));
            continue;
        }
        case OP_SELF:
        {
            StkId rb = RB(i);
            setobjs2s(L, ra + 1, rb);
            Protect(luaV_gettable(L, rb, RKC(i), ra));
            continue;
        }
        case OP_ADD:
        {
            arith_op(luai_numadd, TM_ADD);
            continue;
        }
        case OP_SUB:
        {
            arith_op(luai_numsub, TM_SUB);
            continue;
        }
        case OP_MUL:
        {
            arith_op(luai_nummul, TM_MUL);
            continue;
        }
        case OP_DIV:
        {
            arith_op(luai_lnumdiv, TM_DIV);
            continue;
        }
        case OP_MOD:
        {
            arith_op(luai_lnummod, TM_MOD);
            continue;
        }
        case OP_POW:
        {
            arith_op(luai_numpow, TM_POW);
            continue;
        }
        case OP_UNM:
        {
            TValue *rb = RB(i);
            if (ttisnumber(rb))
            {
                lua_Number nb = nvalue(rb);
                setnvalue(ra, luai_numunm(nb));
            }
            else
            {
                Protect(Arith(L, ra, rb, rb, TM_UNM));
            }
            continue;
        }
        case OP_NOT:
        {
            int res = l_isfalse(RB(i));  /* next assignment may change this value */
            setbvalue(ra, res);
            continue;
        }
        case OP_LEN:
        {
            const TValue *rb = RB(i);
            switch (ttype(rb))
            {
            case LUA_TTABLE:
            case LUA_TROTABLE:
            {
                setnvalue(ra, ttistable(rb) ? cast_num(luaH_getn(hvalue(rb))) : cast_num(luaH_getn_ro(rvalue(rb))));
                break;
            }
            case LUA_TSTRING:
            {
                setnvalue(ra, cast_num(tsvalue(rb)->len));
                break;
            }
            default:    /* try metamethod */
            {
                ptrdiff_t br = savestack(L, rb);
                Protect(
                    if (!call_binTM(L, rb, luaO_nilobject, ra, TM_LEN))
                    luaG_typeerror(L, restorestack(L, br), "get length of");
                )
                }
            }
            continue;
        }
        case OP_CONCAT:
        {
            int b = GETARG_B(i);
            int c = GETARG_C(i);
            Protect(luaV_concat(L, c - b + 1, c); luaC_checkGC(L));
            setobjs2s(L, RA(i), base + b);
            continue;
        }
        case OP_JMP:
        {
            dojump(L, pc, GETARG_sBx(i));
            continue;
        }
        case OP_EQ:
        {
            TValue *rb = RKB(i);
            TValue *rc = RKC(i);
            Protect(
                if (equalobj(L, rb, rc) == GETARG_A(i))
                dojump(L, pc, GETARG_sBx(*pc));
            )
                pc++;
            continue;
        }
        case OP_LT:
        {
            Protect(
                if (luaV_lessthan(L, RKB(i), RKC(i)) == GETARG_A(i))
                dojump(L, pc, GETARG_sBx(*pc));
            )
                pc++;
            continue;
        }
        case OP_LE:
        {
            Protect(
                if (lessequal(L, RKB(i), RKC(i)) == GETARG_A(i))
                dojump(L, pc, GETARG_sBx(*pc));
            )
                pc++;
            continue;
        }
        case OP_TEST:
        {
            if (l_isfalse(ra) != GETARG_C(i))
                dojump(L, pc, GETARG_sBx(*pc));
            pc++;
            continue;
        }
        case OP_TESTSET:
        {
            TValue *rb = RB(i);
            if (l_isfalse(rb) != GETARG_C(i))
            {
                setobjs2s(L, ra, rb);
                dojump(L, pc, GETARG_sBx(*pc));
            }
            pc++;
            continue;
        }
        case OP_CALL:
        {
            int b = GETARG_B(i);
            int nresults = GETARG_C(i) - 1;
            if (b != 0) L->top = ra + b; /* else previous instruction set top */
            L->savedpc = pc;
            switch (luaD_precall(L, ra, nresults))
            {
            case PCRLUA:
            {
                nexeccalls++;
                goto reentry;  /* restart luaV_execute over new Lua function */
            }
            case PCRC:
            {
                /* it was a C function (`precall' called it); adjust results */
                if (nresults >= 0) L->top = L->ci->top;
                base = L->base;
                continue;
            }
            default:
            {
                return;  /* yield */
            }
            }
        }
        case OP_TAILCALL:
        {
            int b = GETARG_B(i);
            if (b != 0) L->top = ra + b; /* else previous instruction set top */
            L->savedpc = pc;
            lua_assert(GETARG_C(i) - 1 == LUA_MULTRET);
            switch (luaD_precall(L, ra, LUA_MULTRET))
            {
            case PCRLUA:
            {
                /* tail call: put new frame in place of previous one */
                CallInfo *ci = L->ci - 1;  /* previous frame */
                int aux;
                StkId func = ci->func;
                StkId pfunc = (ci + 1)->func; /* previous function index */
                if (L->openupval) luaF_close(L, ci->base);
                L->base = ci->base = ci->func + ((ci + 1)->base - pfunc);
                for (aux = 0; pfunc + aux < L->top; aux++) /* move frame down */
                    setobjs2s(L, func + aux, pfunc + aux);
                ci->top = L->top = func + aux; /* correct top */
                lua_assert(L->top == L->base + clvalue(func)->l.p->maxstacksize);
                ci->savedpc = L->savedpc;
                ci->tailcalls++;  /* one more call lost */
                L->ci--;  /* remove new frame */
                goto reentry;
            }
            case PCRC:    /* it was a C function (`precall' called it) */
            {
                base = L->base;
                continue;
            }
            default:
            {
                return;  /* yield */
            }
            }
        }
        case OP_RETURN:
        {
            int b = GETARG_B(i);
            if (b != 0) L->top = ra + b - 1;
            if (L->openupval) luaF_close(L, base);
            L->savedpc = pc;
            b = luaD_poscall(L, ra);
            if (--nexeccalls == 0)  /* was previous function running `here'? */
                return;  /* no: return */
            else    /* yes: continue its execution */
            {
                if (b) L->top = L->ci->top;
                lua_assert(isLua(L->ci));
                lua_assert(GET_OPCODE(*((L->ci)->savedpc - 1)) == OP_CALL);
                goto reentry;
            }
        }
        case OP_FORLOOP:
        {
            lua_Number step = nvalue(ra + 2);
            lua_Number idx = luai_numadd(nvalue(ra), step); /* increment index */
            lua_Number limit = nvalue(ra + 1);
            if (luai_numlt(0, step) ? luai_numle(idx, limit)
                    : luai_numle(limit, idx))
            {
                dojump(L, pc, GETARG_sBx(i));  /* jump back */
                setnvalue(ra, idx);  /* update internal index... */
                setnvalue(ra + 3, idx); /* ...and external index */
            }
            continue;
        }
        case OP_FORPREP:
        {
            const TValue *init = ra;
            const TValue *plimit = ra + 1;
            const TValue *pstep = ra + 2;
            L->savedpc = pc;  /* next steps may throw errors */
            if (!tonumber(init, ra))
                luaG_runerror(L, LUA_QL("for") " initial value must be a number");
            else if (!tonumber(plimit, ra + 1))
                luaG_runerror(L, LUA_QL("for") " limit must be a number");
            else if (!tonumber(pstep, ra + 2))
                luaG_runerror(L, LUA_QL("for") " step must be a number");
            setnvalue(ra, luai_numsub(nvalue(ra), nvalue(pstep)));
            dojump(L, pc, GETARG_sBx(i));
            continue;
        }
        case OP_TFORLOOP:
        {
            StkId cb = ra + 3;  /* call base */
            setobjs2s(L, cb + 2, ra + 2);
            setobjs2s(L, cb + 1, ra + 1);
            setobjs2s(L, cb, ra);
            L->top = cb + 3; /* func. + 2 args (state and index) */
            Protect(luaD_call(L, cb, GETARG_C(i)));
            L->top = L->ci->top;
            cb = RA(i) + 3;  /* previous call may change the stack */
            if (!ttisnil(cb))    /* continue loop? */
            {
                setobjs2s(L, cb - 1, cb); /* save control variable */
                dojump(L, pc, GETARG_sBx(*pc));  /* jump back */
            }
            pc++;
            continue;
        }
        case OP_SETLIST:
        {
            int n = GETARG_B(i);
            int c = GETARG_C(i);
            int last;
            Table *h;
            fixedstack(L);
            if (n == 0)
            {
                n = cast_int(L->top - ra) - 1;
                L->top = L->ci->top;
            }
            if (c == 0) c = cast_int(*pc++);
            runtime_check(L, ttistable(ra));
            h = hvalue(ra);
            last = ((c - 1) * LFIELDS_PER_FLUSH) + n;
            if (last > h->sizearray)  /* needs more space? */
                luaH_resizearray(L, h, last);  /* pre-alloc it at once */
            for (; n > 0; n--)
            {
                TValue *val = ra + n;
                setobj2t(L, luaH_setnum(L, h, last--), val);
                luaC_barriert(L, h, val);
            }
            unfixedstack(L);
            continue;
        }
        case OP_CLOSE:
        {
            luaF_close(L, ra);
            continue;
        }
        case OP_CLOSURE:
        {
            Proto *p;
            Closure *ncl;
            int nup, j;
            p = cl->p->p[GETARG_Bx(i)];
            nup = p->nups;
            fixedstack(L);
            ncl = luaF_newLclosure(L, nup, cl->env);
            setclvalue(L, ra, ncl);
            ncl->l.p = p;
            for (j = 0; j < nup; j++, pc++)
            {
                if (GET_OPCODE(*pc) == OP_GETUPVAL)
                    ncl->l.upvals[j] = cl->upvals[GETARG_B(*pc)];
                else
                {
                    lua_assert(GET_OPCODE(*pc) == OP_MOVE);
                    ncl->l.upvals[j] = luaF_findupval(L, base + GETARG_B(*pc));
                }
            }
            unfixedstack(L);
            Protect(luaC_checkGC(L));
            continue;
        }
        case OP_VARARG:
        {
            int b = GETARG_B(i) - 1;
            int j;
            CallInfo *ci = L->ci;
            int n = cast_int(ci->base - ci->func) - cl->p->numparams - 1;
            if (b == LUA_MULTRET)
            {
                Protect(luaD_checkstack(L, n));
                ra = RA(i);  /* previous call may change the stack */
                b = n;
                L->top = ra + n;
            }
            for (j = 0; j < b; j++)
            {
                if (j < n)
                {
                    setobjs2s(L, ra + j, ci->base - n + j);
                }
                else
                {
                    setnilvalue(ra + j);
                }
            }
            continue;
        }
        }
    }
}

